表格表头随滚动固定插件

$.fn.extend({
    tableHeaderFix:function (option) {
        var params = {
            h:0,
        };
        //更改默认值
        if(option && typeof(option) == 'object'){
            $.each(option,function (i,v) {
                params[i] = v;
            });
        }
        //所有单元格宽度设定
        var cells = $(this).find('th,td');
        $.each(cells,function (i,v) {
            var w = $(v).width();
            $(v).css({'width':w+'px'});
        });
        //获取thead的jquery对象
        var thead = $(this).find('thead');
        var pos = thead.position();
        var thead_w = thead.width();
        //console.log(pos,thead_w);
        //滚动事件
        var thead = $(this).find('thead');
        var thead_w = thead.width();
        $(document).scroll(function () {
            var scroH = $(document).scrollTop();  //滚动高度
            if(scroH > (pos.top - params.h)){
                thead.css({'position':'fixed','top':params.h+'px','width':thead_w+'px','z-index':1});
            }else{
                thead.css({'position':'relative'});
            }
        });
    }
});

调用：$('table').tableHeaderFix({h:0});